Personal hygiene mirrors are a part of every day life to view the face for a variety of reasons. Most significantly, personal hygiene mirrors are used for a self examination of the skin as an aid in improving personal appearance by detecting facial flaws associated with the skin. Identifying problem areas of the skin, the user can then cosmetically address the problems to self-applied hygiene products.
Common personal hygiene mirrors are typically oval or circular supported by a handle or support stand. To improve viewing of the skin, mirrors may include lights embedded within a housing surrounding the mirror to direct light upon the face to aid in viewing the skin. Illuminated mirror manufacturers have devised a variety of methods for illuminating the face of a person positioned close to the mirror. One method positions one or more light sources around the periphery of the mirror. Another approach utilizes an annular light diffuser ring that encircles a mirror in an attempt to evenly distribute the light upon the face. Other solutions include use of a ring-shaped fluorescent light that encircles the entire mirror. Various methods of illuminating mirrors are discussed in the U.S. Pat. No. 6,158,877 entitled “Magnifying Mirror Having Focused Annular illuminator”, issued Dec. 12, 2000, the substance of which is incorporated herein by reference.
A problem inherent to all of the aforementioned illuminated mirrors is the glare associated with the skin's surface impeding the user from visualizing the skin in a more detailed manner. Methods used to reduce the surface reflection from the skin are known in the medical field and are generally referred to as epiluminescence imaging. Cross-polarization or orthogonal polarization is one method of reducing the reflection of the light from the surface of the skin to aid in the examination of the skin. Light emanating from a light source is first linearly polarized, so that the orientation of the light falling on the skin surface is in the same plane of polarization. As the light enters the skin, its polarization angle changes such that the light is reflected from a deeper structure. However, the light reflected from the surface of the skin is still polarized in the same plane as the incident light. By including a second polarizer in the path of the reflected light from the skin, a selective filtering of light can be achieved.
Most of the light directed to the skin's surface is reflected back to the viewer as the refractive index of skin is higher than that of air. The reflection of light, off of the skin, is analogous to the reflection of light off of the surface of water. Accordingly, the information received by the eye carries mostly information about the contour of the skin surface rather than the deeper structures. Remaining light enters the skin and is absorbed or is reflected back in a scattered fashion. By polarizing the incident light with a second of polarizer, the specular component of the reflected light is blocked by the viewing polarizer, thus producing an enhanced view below the skin surface. Accordingly, inflammation, color, pigmentation, hair follicles and blood vessels may be viewed.
When the incident light and the second polarizer are parallel, the surface topography and properties of the skin are highlighted and enhanced. In this regard, if the polarizer in the path of the light from the skin to the eye is polarized in the same orientation of the incident light, only the light from its polarization angle will be viewed. Cross-polarization imaging of the body skin was originally described by R. R. Anderson (“Polarized light examination and photography of the skin.” Archives Dermatology 1991; 127; 1000–1005), the substance of which is incorporated herein by reference.
An example of constructive application of cross-polarization epiluminescence in the medical field is embodied in a device identified as DermLite®, manufactured and marketed by 3Gen, LLC. of Monarch Beach, Calif. With this low cost and easy to use DermLite® Device, screening for cancer by dermatologists in routine clinical examination of skin disease has become a reality. The DermLite® device uses cross-polarization epiluminescence imaging through use of white light emitting diodes (LEDs), a high magnification lens (10×), and a lithium ion battery contained in a small lightweight device.
In the DermLite® device, a window is incorporated into a compact housing and a plurality of white light LEDs encircle a magnifying lens. The DermLite® device incorporates cross-polarization filters that reduce the reflection of light from the surface of the skin and permits visualization of the deeper skin structures. Light from eight (8) LEDs is polarized linearly by a polarizer, which is annular in shape and located in front of the LEDs. The imaging viewed through the magnifying lens is also linearly polarized by using a polarizer that is located in front of the lens. The LEDs have a narrow beam angle that concentrates the light into a small area, pointing the incident light to the center to increase the brightness of the area being viewed. Thus, light from the LEDs passes through the polarizer which enters the skin and reflects back through the viewing polarizer to create cross-polarization allowing examination to look deeper within the skin structure. The DermLite® Platinum™ product, also manufactured by 3Gen, LLC. was developed to provide variable polarization. Variable polarization is achieved by a rotating dial. Rotation of the polarizer to a cross-polarization cancels out the surface reflection for an in-depth look at the deeper pigmentation and lesion structures. Rotation to parallel polarization allows a clear view of the skin surface. The DermLite® Pro DP-R™ also manufactured by 3gen, LLC, was developed to provide instant, button activated, polarization control. Embodiments of the DermLite® Pro DP-R™ are disclosed in U.S. patent application Ser. No. 10/384,110 filed Mar. 7, 2003, the substance of which is incorporated herein by reference. Variable mode polarization is provided by a toggle switch that allows the viewer to view the surface of the skin using a polarizing mode, and a switch creates a cross polarization which cancels out surface reflection for a view of the deeper pigmentation and structures of the skin.
Although, the DermLite®, DermLite® Platinum™ and DermLite® Pro DP-R™ products have been recognized as a major advancement in the art of routing clinical diagnosis and analysis of skin cancer lesions, the DermLite® and DermLite® Platinum™ devices do not provide a mechanism for self-examination of facial skin for cosmetic and/or medical purposes. Thus, there is a great need in the art for a mirror device that will allow self-examination of facial skin for cosmetic and/or medical purposes employing cross-polarized imaging and parallel-polarized imaging and a combination of both. Further there is a great need in the art for a mirror device for self-examination of facial skin that employs cross-polarization and parallel-polarization using epiflourescence with white light and colored or UV light in order to contrast facial skin.